Interactions between consumer and resource diversity under changing environmental conditions

生产者多样性是由消费者的存在（自上而下的监管）还是由资源的可用性（自下而上的监管）控制，一直存在着长期的争论。直到最近，通过荟萃分析对现有研究的综合表明，这两个因素在调节生产者多样性方面存在相互作用。本项目研究了食虫物种多样性对食饵群落物种多样性的影响。食用者对猎物多样性的影响不仅取决于食用者群落的多样性，还与食用者的种类特征和摄食类型等环境因素有关。这些潜在的复杂的消费者和其他环境因素对猎物群落的相互作用将在受控的实验室条件下进行调查，并在中生态和野外实验中以周围植物为资源群落，淡水底栖无脊椎动物（腹足类、等足类、毛翅目、蜉蝣目）为消费者。此外，当不同的猎物种类（在重要的营养成分方面）对消费者的饮食贡献不同时，假设猎物群落的多样性对消费者（混合）猎物组合的营养质量有影响。由于资源的营养质量往往决定了食物网的营养转移效率，因此在消费者层面上，更多样化的猎物组合有望提高营养转移效率和生产力。因此，本项目将生物多样性与生态系统结构之间关系的重要基础问题与利用分子工具评估周边植物群落多样性的创新方法相结合。

There has been a long debate whether producer diversity is controlled by the presence of consumers (top-down regulation) or by the availability of resources (bottom-up regulation). Only recently, syntheses on existing studies via meta-analyses suggested an interaction of both these factors in regulating producer diversity. This project investigates the role of consumer species diversity on the species diversity of a prey community. The effects of the consumers on the prey diversity are expected to not only depend on the diversity of the consumer community, but also on the species identity and feeding type of the consumers and other environmental factors. These potentially complex interactions between consumers and other environmental factors on the prey community will be investigated under controlled laboratory conditions and in mesocosm and field experiments using periphyton as resource community and freshwater benthic invertebrates (gastropods, isopods, trichoptera, ephemeroptera) as consumers. Furthermore, the diversity of the prey community is hypothesized to have impacts on the nutritional quality of the (mixed) prey assemblage for the consumers when different prey species contribute differently (with respect to important nutritional constituents) to the consumers’ diet. Since the nutritional quality of the resource often determines the trophic transfer efficiency in food webs, it is expected that more diverse prey assemblages enhance the trophic transfer efficiency and the productivity on the consumer level. Hence, this project combines important and fundamental questions on the relations between biodiversity and ecosystem structure with the innovative and new methodological approach of using molecular tools for the assessment of periphyton community diversity.